Security systems offer a degree of security for residential sites and for office, business, or industrial applications. Typically, a security device monitoring or controlling a zone is provided as part of a security system. For example, an alarm may be set, which is triggered upon the occurrence of various threat or alarm conditions. At a larger installation, such as in a business, industrial or office setting, more than one zone and security device may be provided at various locations of the site. The security devices are typically connected to a security control panel, which is essentially a control board or control module for security for the site. Also, a remote central monitoring station may be connected, and this central station may be notified when fault, a threat condition, or some other type of security breach, a fire condition, or other type of emergency condition or the like is detected.
In such conventional systems, the problem exists that a security device, such as a motion sensor detector may not be working properly because of a defect. For example, a motion detector or sensor using a pyro element that detects infrared light may get less sensitive over time as the device ages, because the lenses deteriorate and electronics and wires fail. Humidity or moisture can exacerbate the effects of oxidation or aging in wires and electronic devices, as can dust, termites or rodents.
Another problem is that the view of the sensor, such as a motion detector or other sensor that is arranged to sense a disruption in infrared light, microwaves, or other types of electromagnetic radiation may be blocked by objects that are inadvertently placed in its field of view, or the angle at which the sensor is deployed may become disadvantageously changed as a result of the nearby movement of people or objects, or because of the effect of gravity, drafts, or the loosening over time of screws or fasteners used to fasten the sensor to a wall, ceiling or the like. For example, an angle at which a passive IR sensor or dual technology apparatus is deployed in a corner of a room near the ceiling may slowly change because of the effect of gravity on one or more fasteners that fasten the apparatus to the wall or ceiling.
Further, in preparation for a crime or intrusion, or other undesirable occurrence, the view of the sensor may be deliberately blocked or obstructed or the field of view of the sensor may be deliberately changed. As a result, the intended view of a motion detector would no longer correspond to the actual view.
It would be desirable therefore, if such change in view, defect, or obstruction could be detected and reported to a central node or central station.
Another problem is that there may be a redundancy of sensors at a site because of alarm verification, requiring both sensors to be tripped before an event is triggered, which could result in a false sense of security when one or more of the sensors is defective or the field of view is off the mark.